A difficult problem in the art is that of prolonging the serving time for fat-fried foods, and particularly deep fat-fried foods. The serving time after frying such foods varies with the particular food, but generally speaking, the serving time is quite short. While the difficulties engendered with serving time differs somewhat from fried food to fried food, generally common to all of the fried foods is that with prolonged serving time, i.e. the time between frying and serving, the fried foods lose the desired texture. In fried chicken, for example, the chicken, after some prolonged time between frying and serving (serving time), e.g. 10 minutes, will have a somewhat oily and dry taste. Fried seafood, e.g. shrimp, scallops and the like, develop something of a soggy taste, texture and mouth feel with prolonged serving time. Vegetables, e.g. mushrooms, become limp. However, probably French fried potatoes deteriorate more rapidly with prolonged serving time than any other fried food. The deterioration causes the French fried potatoes to not only have an oily and dry taste, but the potatoes also become somewhat limp, as opposed to the fresh potato taste and crispness of the freshly fried potatoes.
The serving time becomes quite critical in many food preparation operations, for example, in fast food restaurants, institutional kitchens and the like. In fast food restaurants, in order to provide such fast service, it is necessary to prepare some of the foods prior to being ordered, and the serving time therefor becomes critical for customer satisfaction. In institutional kitchens and the like, there is always a time lag between preparation of the food and transportation of that food to the consumer.
The art has long struggled with methods, coatings and compositions for prolonging the serving time. These vary with the particular foods involved, but, generally, all of these approaches are toward some protective coating or treatment which will slow the deterioration of the texture and taste of the food after frying. French fried potatoes have been a very difficult problem for the art since certain coatings and the like may be relatively successful for other foods, but when applied to French fried potatoes, those coatings fall far short of desirability.
The reasons for loss of texture and taste of such fried foods have never been clear in the art. Some investigators have asserted that oil infusion into the fried foods is responsible, while others have asserted that loss of moisture from the fried foods is responsible. Most likely, both are responsible for the loss of texture and taste.
Generally speaking, the art has concentrated on water dispersible coating compositions for such fried foods which contain a starch, a stabilizing agent, an acid salt and a leavening agent. The starch, during frying, is presumed to be converted to something of an oil and moisture barrier. The stabilizing agent provides a stable dispersion of the starch in an aqueous medium for applying the coating to the food, and the acid salt is used to prevent discoloration, particularly in regard to French fried potatoes, and may function as part of a leavening system. A leavening agent is used to provide a somewhat crispy texture.
However, the prior art approaches have not been entirely satisfactory, especially for French fried potatoes, since it is quite common for French fried potatoes for use by fast food restaurants and institutional kitchens to be partially fried (parfried) in hot oil and then quick frozen for shipment to the user. This allows a very quick frying of the potatoes in hot oil by the user, e.g. a fast food restaurant. During the time period from parfrying and freezing by the manufacturer to refrying (finish frying) by the user, even in the frozen condition, there is opportunity for residual oil from the parfrying and moisture in the food to pass through the coating. Thus, when the refrying (finish frying) is achieved, by the ultimate user, there is already a certain amount of oil infusion and moisture loss associated with the potatoes, and the additional oil infusion into and the moisture loss from the potatoes during finish frying and during the serving time can make the serving time quite short. Similar parfrying and freezing takes place with other foods designed for fast food restaurants and institutional use, e.g. chicken, seafood, vegetables, etc.
In U.S. Pat. No. 3,424,591, issued on Jan. 28, 1969, it is pointed out that potatoes have a variable chemical and physical composition, e.g. the amount of reducing sugars, moisture, solids, protein, carbohydrate, etc., and that a sugar, such as dextrose or glucose, is often used in coatings for the potatoes to avoid the affects of some of that variation by providing a richer color to the fried potatoes. It is also pointed out that calcium lactate can be used as a stiffening agent to improve the physical appearance and plate life (serving time). To avoid these problems, that patent suggests treating the potatoes with a chemically modified natural hydrocolloid to form a thin coating or film on the potato surface prior to deep fat frying. Particularly recommended is alkyl cellulose ether as the hydrocolloid, and particularly those which form thermally reversible gels in aqueous solution, such as methylcellulose.
U.S. Pat. No. 3,751,268, issued on Aug. 7, 1973, recognizes the same problem with serving time of French fried potatoes and points out that prior attempts include coating the potatoes before frying with gelatinized starch solution of either a modified or unmodified starch, but that practice has proved ineffective. The patent suggests coating the potatoes with ungelatinized unmodified high amylose starch having an amylose content above 50%. In this regard, the patent points out that it is intended that the starches have a pure amylose content of more than 50% and the starches have undergone no physical or chemical treatment to change the properties of the refined native starch.
U.S. Pat. No. 4,551,340, issued on Nov. 5, 1985, again addresses the problem of French fried potatoes and suggests that the potatoes be wetted with an aqueous suspension of a film-forming hydrocolloid, glucose polymer, most preferable potato starch, which has not been pregelatinized. It is said that that hydrocolloid film functions not only to minimize oil absorption but also to control moisture loss during frying and in oven reheating.
U.S. Pat. No. 5,004,616, issued on Apr. 2, 1991, describes a process for preparing improved French fried potatoes for subsequent reheating in a microwave oven where the potatoes are toasted with potato granules to provide a thin coating of toasted potato granules which adheres to the surface of the potato strips. After the potato strips are blanched (described more fully hereinafter), the potatoes are dust coated with the potato granules. Thus, the protective coating is a potato starch.
U.S. Pat. No. 5,059,435, issued Oct. 22, 1991, addresses the same problem and reviews the prior art in connection with the coatings. Particularly, that patent addresses the ungelatinized modified high amylose starch described in U.S. Pat. No. 3,751,268, discussed above, but suggests a different coating. The patent suggests a coating comprising a combination of chemically modified ungelatinized potato starch, chemically modified ungelatinized cornstarch, and rice flour. It is stated in that patent that the potato starch in the composition functions to produce optimal results. Particularly, it is said that raw potato starch which has been modified through known chemical cross-linking processes produces an optimal coating, since it minimizes sticking or clumping of the strips during processing and coats the potato strips evenly. It is further said that the combination of the ungelatinized potato starch, modified ungelatinized cornstarch, and rice flour is important, since the potato starch and cornstarch contribute crispness to the coating since they are not gelatinized prior to parfrying, and the rice flour provides tenderness to the finished product.
U.S. Pat. No. 5,302,410, issued on Apr. 12, 1994, reports that the prior approaches for French fried potatoes by using gums, high amylose starches and other hydrocolloids have not fulfilled expectations and suggests coating the potatoes before parfrying with an aqueous solution of the hydrolyzed starch product such as dextrin or maltodextrin.
U.S. Pat. No. 5,393,552, issued on Feb. 28, 1995, is a continuation-in-part of U.S. Pat. No. 5,302,410 and suggests the same coating but used in a variation of the process.
Accordingly, the art has long struggled toward providing an acceptable coating for fat-fried foods, especially deep fat-fried foods, which will prolong the serving time, but as the prior art discussed above illustrates, the art has not produced a satisfactory coating, and many different approaches have been used in efforts to solve the problem of prolonged serving time. It would, therefore, be of distinct advantage to the art to provide a coating for fried foods, particularly French fried potatoes, which allows a much longer serving time while yet retaining the fresh fried appearance, texture and taste.